The article presents polymer optical fibre with sensitive luminescence cladding used for ultraviolet detection. The construction of polymethyl metacrylate (PMMA) fibre coated by organic dye doped polyurethane film is presented. The Tinopal (fluorescent optical brightener) incorporated into the polyurethane coating was used as UV indicator. The chosen dye allowed to direct UV-A detection with luminescence emission in visible range. The construction and fabrication process of UV sensitive polymer fibre is shown. The experimentally obtained characteristic using Nd: YAG (355nm) is presented. The high relative sensitivity up to 0.27mW -1 was obtained. It has been pointed potential applications of fabricated senor.Keywords: Polymethyl methacrylate (PMMA), polymer optical fibre (POF), luminescent based sensor, optical fibre sensor, UV sensor, Tinopal
INTRODUCIONThe safety conditions of environmental monitoring for health protection have a high impact in optoelectronics detectors technology. The Sun radiation is important parameter of environmental monitoring. The World Health Organization defined UVA-UVC radiation ranges. The UV-C (100 -280nm) and UV-B (280 -315nm) are highly attenuated by the atmosphere but almost 90% of UV-A (315 -400nm) reach the earth's surface. The UV radiation has to be monitored because it causes e.g. the cancer skin risk and eye diseases [1]. The ultraviolet radiation is also used for scientific research, medicine, industry. It is used in water sterilization and food disinfection applications [2-3], automatic fire and explosion protection systems [4], combustion monitoring for energy production and many industrial treatment processes (curing technology [5], biodiesel production [6], UV lasers technology [7,8]). The invisible UV radiation has to be measured in above applications to assure health and safety working conditions. There are many conventional sensors such as photodiodes, phototransistors or photo multiplier tubes for UV detection [9][10][11]. They assure high price-performance ratio for many typical applications. Unfortunately they offer a single point measurement and can't be used in hazardous environments (explosion danger or strong electromagnetic field areas). The optical measurement techniques have been developed to use in above cases. The luminescence phenomenon in optical materials allows to convert electromagnetic radiation into the range suitable for electronic detectors (typically visible and near infrared range). The construction of sensing element depends on the application field. The ultraviolet luminescence conversion is used in many fields of microscopic detection for biology and medicine. The sensing structures, typically solutions of luminescent organic dyes or nanoparticles, are used for different techniques luminescent imaging which improves observation contrast and allows to trace in situ chemical and biological reactions [12]. The sensors for automation and industrial applications are based mostly on thin films or optical fibre technology [13][14][15]. The most com...